DESIGN AND ANALYSIS OF COMPOSITE STRUCTURES

Transcription

1 DESIGN AND ANALYSIS OF COMPOSITE STRUCTURES WITH APPLICATIONS TO AEROSPACE STRUCTURES Christos Kassapoglou WILEY A John Wiley anil Sons, Ltd, Publication

2 Contents About the Author ix Series Preface x Preface xi 1 Applications of Advanced Composites in Aircraft Structures 1 References 7 2 Cost of Composites: a Qualitative Discussion Recurring Cost Nonrecurring Cost Technology Selection Summary and Conclusions 27 Exercises 30 References 30 3 Review of Classical Laminated Plate Theory Composite Materials: Definitions, Symbols and Terminology Constitutive Equations in Three Dimensions 35 3,2.1 Tensor Transformations Constitutive Equations in Two Dimensions: Plane Stress 39 Exercises 52 References 53 4 Review of Laminate Strength and Failure Criteria Maximum Stress Failure Theory Maximum Strain Failure Theory Tsai-Hill Failure Theory Tsai-Wu Failure Theory Other Failure Theories 59 References 60 5 Composite Structural Components and Mathematical Formulation Overview of Composite Airframe The Structural Design Process: The Analyst's Perspective 64

3 5.7.2 Basic Design Concept and Process/Material Considerations for Aircraft Parts Sources of Uncertainty: Applied Loads, Usage and Material Scatter Environmental Effects Effect of Damage Design Values and Allowables Additional Considerations of the Design Process Governing Equations Equilibrium Equations Stress Strain Equations Strain-Displacement Equations von Karman Anisotropic Plate Equations for Large Deflections Reductions of Governing Equations: Applications to Specific Problems Composite Plate Under Localized in-plane Load Composite Plate Under Out-of-Plane Point Load Energy Methods Energy Expressions for Composite Plates 107 Exercises 113 References Buckling of Composite Plates Buckling of Rectangular Composite Plate under Biaxial Loading Buckling of Rectangular Composite Plate under Uniaxial Compression Uniaxial Compression, Three Sides Simply Supported, One Side Free Buckling of Rectangular Composite Plate under Shear Buckling of Long Rectangular Composite Plates under Shear Buckling of Rectangular Composite Plates under Combined Loads Design Equations for Different Boundary Conditions and Load Combinations 138 cises 141 rences 143 Post-Buckling 145 Post-Buckling Analysis of Composite Panels under Compression Application: Post-Buckled Panel Under Compression Post-Buckling Analysis of Composite Plates under Shear Post-buckling of Stiffened Composite Panels under Shear Post-buckling of Stiffened Composite Panels under Combined Uniaxial and Shear Loading 171 Exercises 174 References Design and Analysis of Composite Beams Cross-section Definition Based on Design Guidelines Cross-sectional Properties Column Buckling 188

4 8.4 Beam on an Elastic Foundation under Compression 8.5 Crippling One-Edge-Free (OEF) Crippling No-Edge-Free (NEF) Crippling Crippling under Bending Loads Crippling of Closed-Section Beams 8.6 Importance of Radius Regions at Flange Intersections 8.7 Inter-rivet Buckling of Stiffener Flanges 8.8 Application: Analysis of Stiffeners in a Stiffened Panel under Compression Exercises References Skin-Stiffened Structure Smearing of Stiffness Properties (Equivalent Stiffness) Equivalent Membrane Stiffnesses Equivalent Bending Stiffnesses Failure Modes of a Stiffened Panel Local Buckling (Between Stiffeners) Versus Overall Panel Buckling (the Panel Breaker Condition) Skin-Stiffener Separation Additional Considerations for Stiffened Panels 'Pinching' of Skin Co-Curing Versus Bonding Versus Fastening 251 Exercises 253 References Sandwich Structure Sandwich Bending Stiffnesses Buckling of Sandwich Structure Buckling of Sandwich Under Compression Buckling of Sandwich Under Shear Buckling of Sandwich Under Combined Loading Sandwich Wrinkling Sandwich Wrinkling Under Compression Sandwich Wrinkling Under Shear Sandwich Wrinkling Under Combined Loads Sandwich Crimping Sandwich Crimping Under Compression Sandwich Crimping Under Shear Sandwich Intracellular Buckling (Dimpling) under Compression Attaching Sandwich Structures 279 Exercises References Core Ramp-Down Regions Alternatives to Core Ramp-Down

5 11 Good Design Practices and Design 'Rules of Thumb' Lay up/stacking Sequence-related Loading and Performance-related Guidelines Related to Environmental Sensitivity and Manufacturing Constraints Configuration and Layout-related 292 Exercises 294 References 295 Index 297